GPR68, or the ovarian cancer G protein-coupled receptor 1 (OGR1), so called as it was first cloned from an ovarian cancer cell line [227], stimulates the accumulation of inositol phosphates and mobilization of intracellular Ca2+ in response to extracellular acidosis within the range of pH 7.6–6.8 [228]. Here, GPR68 is linked to ovarian cancer.